Number of orbits of length n under the map whose periodic points are counted by A001642.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =5a(6) =9a(7) =13a(8) =23a(9) =36a(10) =63a(11) =101a(12) =175a(13) =290a(14) =497a(15) =840a(16) =1445a(17) =2460a(18) =4247a(19) =7293a(20) =12619a(21) =21805a(22) =37856a(23) =65695a(24) =114401a(25) =199280a(26) =347944a(27) =607959a(28) =1064130a(29) =1864083